New nanomechanical oscillators with record low losses

New nanomechanical oscillators with record low losses

Scanning electron micrograph of a polygonal resonator. The insert shows the shape of the perimeter mode. Credit: Mohammad J. Bereyhi (EPFL)

The vibration modes of nanomechanical resonators are analogous to different guitar string notes and have similar properties such as frequency (high pitch) and life. Life is characterized by the quality factor, which is the number of oscillations of the resonator, while its energy is reduced by 70%. The quality factor is crucial for modern applications of mechanical resonators, as it determines the level of thermal noise, which is the limit for accounting for weak forces and monitoring quantum effects.

Now EPFL scientists led by Professor Tobias J. Kippenberg, show that a regular polygon, suspended at its vertices, maintains vibration modes around the perimeter with extremely high quality factors. This is a consequence of the geometric symmetry of regular polygons, combined with the elastic properties of stressed structures. This approach to loss engineering has an important advantage over previous techniques: realizing high-quality factors in much smaller devices.

“The new perimeter modes not only beat the record for the highest quality factor, but are almost 20 times more compact than devices with similar performance,” said Nils Engelsen, senior author of the study. “Compactness comes with real practical benefits. In our laboratory we try to measure and control mechanical vibration at the quantum level with the help of light, which requires the suspension of mechanical resonators less than one micrometer from a structure that directs light. This feat is much simpler with compact devices. “

The uncomplicated design of the polygonal resonators allows the authors to take another step forward and make a circuit of connected polygonal resonators. This circuit of connected oscillators can behave strikingly differently from a single resonator. The authors study the specific dynamics of this circuit, which arises from the way the resonators are connected.

Accurate force reading is an important application of nanomechanical resonators. By measuring the fluctuations of the polygon position resonator with the help of optical interferometer, the authors demonstrate that these resonators can measure force fluctuations up to 1 atonewton. This level of sensitivity is close to that of the most modern atomic force microscopes.

“We hope that the demonstrated sensitivity to the power of polygons, combined with their compactness and simplicity, will inspire their use in real power microscopes,” said Mohammad Bereihi, who led the study. Physical examination X.

“So far, improvements in mechanical quality factors have come at the cost of increased size and increased design complexity, making state-of-the-art devices very difficult to manufacture. It’s a different story with perimeter modes. I believe that the simplicity of this new design greatly expands its potential for finding new and promising applications. ”

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More information:
Mohammad J. Bereyhi et al, The perimeter regimes of nanomechanical resonators show quality factors exceeding 109 at room temperature, Physical examination X (2022). DOI: 10.1103 / PhysRevX.12.021036

Quote: New nanomechanical oscillators with record low losses (2022, May 12), extracted on May 13, 2022 from

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